1. Field of the Invention
The present invention relates to a bubble creating method, a bubble creating device, a bubbly fixation fluid producing method, a bubbly fixation fluid producing device, a fixation fluid, an image forming method, and an image forming apparatus.
2. Description of the Related Art
An image forming apparatus such as printers, facsimile machines and copying machines is an apparatus for forming an image including a character or a symbol on a recording medium such as paper, cloth and OHP sheets based on image information. Particularly, electrophotographic image forming apparatuses have been widely used in offices since a high definition image can be formed on a normal paper sheet at a high speed. In such an electrophotographic image forming apparatus, a thermal fixation method has been widely used in which toner is fixed on a recording medium by heating and melting the toner on the recording medium and pressurizing the melted toner. The thermal fixation method has been used preferably since there may be provided, for example, a high fixation speed and a high fixed-image quality.
However, about half or more of electric power consumption in such an electrophotographic image forming apparatus may correspond to consumptions for heating toner in the thermal fixation method. Meanwhile, a fixation device with a low electric power consumption (energy saving) is desired from the viewpoint of dealing with environmental problems in recent years. That is, a fixation method is desired which is not required to lower a toner-heating temperature extremely than ever or heat toner so as to fix the toner. Particularly, a non-heating fixation method for fixing toner on a recording medium without heating the toner at all is ideal in terms of low electric power consumption.
For such a non-heating fixation method, for example, a wet-type toner fixation method is proposed in Japanese Patent No. 3,290,513 in which a oil-in-water-type fixing agent capable of dissolving or swelling toner in which an organic compound insoluble or hard to be dissolved in water is dispersed in and mixed into water is sprayed or dropped onto the surface of a substrate on which unfixed toner is arranged at predetermined positions so as to dissolve or swell the toner and subsequently the substrate is dried.
However, since an oil-in-water-type fixing agent in which an organic compound insoluble or hard to be dissolved in water is dispersed and mixed in water is used in the wet-type fixation method in Japanese Patent No. 3,290,513, the water content of the fixing agent may be absorbed into a recording medium (substrate) such as transfer paper sheets and cockle or curl may be generated in the recording medium when a large quantity of the fixing agent is applied on unfixed toner. Accordingly, stable and high-speed delivery of recording medium which is required for an image forming apparatus may be deteriorated significantly. Then, if the water content of a fixing agent applied on a recording medium is removed by evaporating a large quantity of water contained in the fixing agent using a dryer, an electric power comparable to the electric power consumption of an image forming apparatus in which the thermal fixation method is used may be required.
Also, for a fixation fluid that does not repel a water-repellency treated and unfixed toner, some oily fixation fluids have been proposed conventionally in which a material for dissolving or swelling toner is dissolved in a oily solvent. For one example of them, a fixation fluid in which an aliphatic dibasic acid ester or the like as a material component for dissolving or swelling a resin component constituting a toner is diluted (or dissolved) by a non-volatile dimethylsilicone as a diluent (or solvent) is proposed in Japanese Patent Application Publication No. 2004-109749. Also, a solution for fixation of an unfixed toner image in a miscible condition which is obtained by mixing 8-120 parts by volume of a silicone oil with 100 parts by volume of a solvent dissolving a toner and having a miscibility with the silicone oil is proposed for a fixation solution that may be used for a fixation method capable of fixing an unfixed image formed by an electrostatic method on an image-receiving sheet clearly and easily without disturbing the image, in Japanese Patent Application publication No. S59-119364. Since such an oily fixation fluid contains an oily solvent having a high affinity with a water-repellency treated and unfixed toner, the water-repellency treated and unfixed toner may be dissolved or swelled without repelling the toner so as to fix the toner on a recording medium.
Any of Japanese Patent No. 3,290,513, Japanese Patent Application Publication No. 2004-109749 and Japanese Patent Application publication No. S59-119364 provides a configuration for applying a fluid on an unfixed toner layer. However, as shown in FIGS. 14A and 14B, when the thickness of a fixation fluid layer 4 on an application roller 1 is less than that of an unfixed toner layer 3 in order to provide a small amount of the fixation fluid on a recording medium 2 in the configuration for applying a fixation fluid on the unfixed toner layer 3 on the recording medium 2 by using the application roller 1 as a contact providing device, unfixed toner particles may be attracted by surface tension caused by a fluid film of the fixation fluid on a surface of the application roller 1 at a position where the application roller 1 leaves from the recording medium 2 and the toner particles may be offset to a surface of the application roller 1, so that an image on the recording medium 2 may be significantly disturbed. On the other hand, when the thickness of a fixation fluid layer 4 on an application roller 1 is sufficiently more than that of an unfixed toner layer 3 as shown in FIG. 15, surface tension caused by a fluid film on a surface of the application roller 1 may not easily and directly act on a toner particle due to a higher amount of the fluid at a position where the application roller 1 leaves from the recording medium 2 and a toner may not be offset to the roller side. However, since a higher amount of a fixation fluid is applied on a paper surface, the toner particles may be drifted by an excess amount of the fixation fluid on the recording medium 2 so that image deterioration may be caused or a drying time may be longer so that a problem may be caused in fixation responsiveness. Also, significant feel of remaining fluid on a paper sheet (wet feel when the paper sheet is touched) may be caused. Furthermore, when the fixing fluid contains water and its application amount on a cellulose-containing medium such as paper sheets is large, a recording medium such as paper sheets may be curled significantly so that jam of an apparatus such as image forming apparatuses may occur which may be caused by a recording medium such as paper sheets at the time of delivery of the recording medium in the apparatus.
Therefore, it may be extremely difficult to attain both application of a small amount of fixation fluid on a toner layer on a paper sheet for improvement of fixation responsiveness, reduction of feeling of remaining fluid and prevention of curling and prevention of toner offset to a fixation roller, in the configuration for conducting roller application of such a fixation fluid. Additionally, when a die coating device, a blade coating device or a wire bar coating device is used as a contact application device and the amount of a fixation fluid is small, toner may also be offset to the contact application device due to the surface tension.
As described above, it may be extremely difficult to attain both application of a small amount of a fixation fluid on a toner layer on a paper sheet for improving fixation responsiveness and uniform application without disturbing a toner image by a conventional formulation of a fixation fluid and a contact application device.
The inventors have conceived of an idea to provide a fixation fluid for a resin fine particle which may conduct fixation of a resin-containing fine particle such as a toner on a medium such as a paper sheet quickly after the fixation fluid may be applied on the medium to which the resin fine particle may be attached while no resin fine particle on the medium may be disturbed and to conduct application of its small amount such that no feel of remaining fluid on the medium may be caused, and a fixation method and fixation device and image forming method and image forming apparatus using the fixation fluid.
Also, the inventors have conceived of an idea to provide a bubbly fixation fluid producing method and device which may have a bubble with a diameter of a desired size during a short time period while a liquid fixation fluid may be used in a container.